The family of "Selena" star Lupe Ontiveros is incredibly upset she was left out of last night's "In Memoriam" presentation at the Oscars ... despite appearing in dozens of major films over the past 30 years.

Ontiveros -- who passed away in July 2012 --  had roles in "Real Women Have Curves", "As Good as it Gets", and "The Goonies" ... but is best known for her role as Yolanda Saldivar, the woman who murdered Selena.

Ontiveros' son Elias tells TMZ ... the whole family gathered to watch the awards show -- and was "disappointed" Lupe wasn't given her proper due -- especially considering some lesser-known people were honored over his mom.

You'll recall, George Clooney did warn some artists might be left out when introducing the tribute, saying, "For for those friends who are on this list tonight, and many others who aren't, we thank you for the memories."

Other celebs snubbed along with Ontiveros -- Andy Griffith, director Gore Vidal, Sherman Hemsley, athlete-turned-actor Alex Karras, and Sylvia Kristel.

"Selena" actress Lupe Ontiveros was laid to rest at a funeral in Southern California today ... surrounded by family, politicians and some of her famous friends.

Lupe's "Desperate Housewives" co-star Eva Longoria was among the famous faces ... along with Wilmer Valderrama and Edward James Olmos ... who appeared with Lupe in a Broadway play.

As we previously reported, Lupe -- who famously portrayed Selena's killer in the 1990 biopic -- passed away on July 26 ... after a battle with liver cancer.

She was 69 years old.

Jennifer Lopez has released a statement, saying, "I am tremendously saddened by the news of Lupe's passing! I've enjoyed her work throughout the years. She was a great actress and working with her in Selena was an unforgettable experience. She will truly be missed."


Prolific Mexican-American character actress Lupe Ontiveros, best known for playing the convicted murderer of the Tejano singer in "Selena," has died. She was 69.

Ontiveros was reportedly suffering from liver cancer. 

Lupe's "Selena" co-star Jacob Vargas was at her bedside last night and tweeted, "My friend Lupe Ontiveros just passed away. May you rest in peace. Thank you for your great contribution to film and TV. You will be missed."

Some of Lupe's long list of other credits include "The Goonies," "As Good As it Gets," Hill Street Blues" and "Desperate Housewives" -- for which she was nominated for an Emmy.

Ontiveros is survived by her husband and three adult children.